agent: update for new Docker release (#1576)

Author: bmpngrok

docs/agent/changelog.md

@@ -6,6 +6,11 @@ title: Changelog
 
 ## v3
 
+### ngrok agent 3.28.0 \[2025-09-11\]
+
+- Updated Docker build base
+- Restored support for `PROXY` in TCP/TLS tunnels
+
 ### ngrok agent 3.27.0 \[2025-08-28\]
 
 - Optimized agent ui.

docs/agent/version-support-policy.mdx

@@ -44,6 +44,7 @@ Extended support beyond LTS is available to customers on a commercial basis. It
 
 | Support Status | Release | Release Date | Latest | Active Support | End of Life |
 | -------------- | ------- | ------------ | ------ | -------------- | ----------- |
+| Active         | 3.28x   | 2025-09-11   | 3.28.0 | 2026-09-11     | 2027-01-11  |
 | Active         | 3.27x   | 2025-08-28   | 3.27.0 | 2026-08-28     | 2026-12-28  |
 | Active         | 3.26x   | 2025-08-07   | 3.26.0 | 2026-08-07     | 2026-10-07  |
 | Active         | 3.25x   | 2025-08-01   | 3.25.1 | 2026-08-01     | 2026-10-01  |

docs/whats-new.mdx

@@ -12,6 +12,10 @@ You can expect this page to update regularly (at least monthly). We'll include t
 - Changes to our API
 - Major security fixes
 
+## September 2025
+
+- 2025-09-11 - Docker images are now based on Debian Bookworm, and `PROXY` support restored for TLS/TCP connections in agents
+
 ## August 2025
 
 - 2025-08-28 - Released [ngrok Agent v3.18.1](/agent/changelog/#ngrok-agent-3270---2025-08-28).